Fine-tuning the matte
Roto Brush does a pretty good job, but there may be stray bits of background in the matte, or
foreground areas that weren’t included. You’ll clean those up by refining the edge.
Adjusting the Roto Brush & Refine Edge effect
When you use the Roto Brush tool, After Effects applies the Roto Brush & Refine Edge effect to
the layer. You can modify the effect using settings in the Effect Controls panel. You’ll use those
settings to further refine the edge of the matte.
1. Press the spacebar to play the clip in the Layer panel; press the spacebar again to end the
preview when you’ve seen the whole clip.As you preview the clip, you may notice that the segmentation boundary area jumps around quite
a bit. You’ll use the Reduce Chatter setting to make it smoother.
2. In the Effect Controls panel, increase the Feather amount to 10 , and increase Reduce
Chatter to 20%.The Reduce Chatter value determines how much influence the current frame has when
performing a weighted average across adjacent frames. Depending on how tight your matte was,
you may need to increase Reduce Chatter to 50%.
3. Preview the clip again. Notice how much smoother the edge of the matte has become.Refine Soft Matte and Refine Hard Matte effects
After Effects includes two related effects for refining mattes: Refine Soft Matte and Refine
Hard Matte. The Refine Soft Matte effect does the same thing as Refine Edge Matte, except
it applies the effect to the entire matte at a constant width. If you need to capture subtle